The Grey Mountains (or Ered Mithrin in Sindarin) was a large mountain range to the north of Rhovanion. They were the last remnants of the wall of the Iron Mountains, which once stretched all over the north of Middle-earth, but were broken at the end of the First Age.

Description, and Geography

North of the Grey Mountains lay the Northern Waste. This land was known as Dor Daedelos during the First Age, but most of it was destroyed in the breaking of Arda.

The eastern end of the Grey Mountains was split in two branches, and in between lay the Withered Heath, where Dragons still bred. After that was a long gap, until the Iron Hills continued the old line of the Iron Mountains again. Erebor, the Lonely Mountain, was not part of either range.

From east to west the mountains stretched some 350 Númenórean Miles, and the sources of the Great River Anduin, the river Greylin, and the Forest River of Mirkwood arose in this range.

History

After fleeing Khazad-dum Durin's folk scattered, and later gathered again in the Grey Mountains, but after six hundred years all the Dwarven strongholds had been abandoned or raided during the Wars of the Dwarves and Dragons. Its sole purpose now seemed to be to divide Forodwaith from Wilderland. Although it seems that the Orcs started moving into the mountains after the Dwarves fled, and were a large threat until after the Battle of Five Armies.

It seems that some Dwarves still dwelt in the Ered Mithrin during the late Third Age. So it is likely after the War of the Ring, the Dwarves drove whatever Drakes and Orcs were left totally from the mountains, and reclaimed the rest of their halls and mines in the Grey Mountains.